on trash I tend to Quelling > Release > Straight > Bloodletter > Wind Bite > Venimous > Rain > Flaming > (varies either burn down one, or spread Dots for Bloodletter)

on bosses it's fairly similar... I tend to save the other cooldowns for when I have to burn down an add. I do try to keep up Rain to make life easier on my healer/tank even though it eats my TP.